1. Technical Field
The present invention relates generally to the field of workload partitions (WPARs) and more particularly to systems and computer program products for allocating resources to a WPAR that is relocated from a departure logical partition (LPAR) to an arrival LPAR such that the relocated WPAR is allocated substantially the same amount of the resource on the arrival LPAR as it was allocated on the departure LPAR.
2. Description of the Related Art
A logical partition (LPAR) is the division of a computer's processors, memory, storage, and input/output into multiple sets of resources so that each set of resources can be operated independently with its own operating system instance and applications. The number of logical partitions that can be created depends on the system's processor model and resources available. Typically, partitions are used for different purposes such as database operations or client/server operations or to separate test and production environments. Each LPAR can communicate with the other LPARs as if the other LPAR is in a separate machine. Logical partitioning allows the computer's resources to be used more efficiently.
Recently, virtualization technology has been expanded with workload partitions (WPARs). WPAR technology allows administrators to virtualize their operating system, which allows for fewer operating system images on a partitioned server. Prior to WPARs, an administrator would need to create a new LPAR for each new isolated environment. Every LPAR requires its own operating system image and a certain number of physical resources.
WPARs are much simpler to manage than LPARs. The greatest shortcoming of LPARs is the need to maintain multiple operating system images, which may lead to over-committing expensive hardware resources. While partitioning helps to consolidate and virtualize hardware within a physical machine, operating system virtualization through WPAR technology goes further and allows for an even more granular approach of resource management.
One of the advantages of using WPARs is that they may be moved or relocated from one LPAR to another easily and transparently. The relocating WPAR is check-pointed on the departure LPAR and then restarted on the arrival LPAR. Each WPAR running on an LPAR is allocated a set of the LPAR's resources, such as processors and memory. Resources may be allocated in either a share basis or a percentage basis. Currently, when a WPAR is relocated, there is no mechanism for ensuring that it is allocated as much of a particular resource on the arrival LPAR as it was allocated on the departure LPAR.